This invention relates generally to an improvement in a thrust reverser for an aircraft jet engine, and more particularly but not by way of limitation, to a novel blocker door frame pressure structure for a translating cowl of a cascade type thrust reverser for an aircraft jet engine.
In the field of thrust reversers for large aircraft jet engines, a common type is one generally known as a cascade thrust reverser which is intended for application to a high bypass gas turbine jet engine. Such a cascade thrust reverser may be deployed upon landing of the aircraft to reverse the fan bypass air forwardly and to thereby slow the speed of the aircraft upon landing and to reduce the roll of the aircraft along the runway. A cascade thrust reverser commonly includes a translating cowl which may translated aft upon landing to deploy a plurality of blocker doors arranged circumferentially around the inner panel of the translating cowl into a bypass fan air blocking position. As such blocking doors are deployed as the translating cowl is moved aft, a plurality of cascades are exposed which redirect the blocked bypass fan air forwardly and outwardly in a controlled manner to provide braking force for the aircraft upon landing.
The translating cowl interfaces at its forward edge with the fixed structure of the thrust reverser, namely the torque box, at its aft edge with the common nozzle, at its upper edges with the pylon, and also interfaces at its lower edge with other thrust reverser structure.
The cascade thrust reverser includes, in addition to the translating cowl, a fixed structure which supports the translating cowl as it is slid aft, thrust reverser actuator means which cooperate with the fixed fan cowl to slide the translating cowl to deployed and stowed positions, and a trailing structure which cooperates with the core cowl surrounding the gas turbine jet engine to provide a nozzle for the bypass fan air.
The outer panel of the translating cowl provides a smooth airflow surface and is presently fabricated from a graphite/epoxy, honeycomb core bondment with various fittings and structure for attachment to the inner panel of the translating cowl, the inner fixed structure and the actuators for the translating cowl.
The inner panel of the translating cowl in its stowed position provides a smooth airflow surface for fan bypass air and maintains the bypass air pressure by means of a honeycomb pressure shelf structure which cooperates with appropriate seal means to preclude bypass fan air from leaking through the interface between fixed structure of the thrust reverser termed the torque box and the translating cowl. The pressure shelf and inner panel structure is provided with pockets for receiving the blocker doors when they are in a stowed position. These pockets for receiving the blocker doors are currently provided by bonding together a number of detail sheet metal and honeycomb core detail parts that are adhesively bonded "piggy-back" into the same basic inner panel to make a inner panel bonded assembly having an integral pressure shelf.
Commonly a bonding tool termed a "throw in block" has secured to it a number of such detail parts and is positioned in the inner panel assembly for the bonding operation, after which the throw in tool is removed from the inner panel bonded assembly. Also, after bonding, the openings for receiving the machined blocker doors are hand routed into the pocket assemblies. The panel termed the integral pressure shelf is bonded to the inner panel to seal off any fan air that might tend to leak into the interior of the translating cowl. The pressure shelf may be constructed as a separate panel and mechanically attached to the inner panel. In addition to being time consuming and expensive to build, this construction also causes difficultly in the interchangibility of the plurality of blocker doors to the thrust reverse since a machined door is required, in this arrangement, to fit into a hand routed opening, the dimensions of which can vary in manufacture.
Accordingly, the purpose of the present invention is to resolve the shortcomings of the present cascade type thrust reverser translating cowl by replacing the pressure shelf structure and the included blocker door pocket construction of the prior art with a novel one piece door frame detail having an integral web to seal off fan air from leakage there by and thereby materially improving the manufacturability and simplifying the construction by substantially reducing the part count while also reducing the cost of the translating cowl.